Do PICKUPS really lose their umph?

[Dennisthe Menace]

Hey gang, what are your thoughts on this? Every once in a while, when I'm in a Music Store, I will hear someone mention to a Salesguy, that their pickups are 'going bad' and he tells the guy he thinks that the magnet(s) are losing their umph . So the guy buys new p'ups from the Sales Guy hoping to improve his guitar sound....... I've heard of having to replace p'ups for maybe a different kind of sound (i.e. something with a little more high end, midrange, etc) that could not be corrected with EQ on the
amp......but....Well again, any thoughts???

[Desert Surfer]

Yeah, it happened to me once on my 1995 ESP US Custom Shop Vintage Plus T (telecaster). All of the sudden, the bridge pickup was losing sound, it came on and off. When I pressed my finger on the pickup for a while, it came back again. But after a few hours, the sound got lost again. My guitar tech guy told me either to have the pickup rewound or replaced. It is not a vintage model so I finally replaced with the exact same pickup (a Seymour Duncan Vintage). Cost me close to $100.

So far the pickups on my Vintage guitars are fine. Knock on wood.

[dubtrub]

I've never had it happen to any of my guitars, but I have read in various guitar tech books that the alnico magnets can lose their strength. I know that I have measured the ohm resistance on some older Strats that I've worked on and found them to be down in the 3-4 ohm range. This obviously is not standard for Fender. My guess would depend on what elements the pickups had been expose to in order to cause such a loss of magnetism or more likely corrosion on the windings from booze and sweat rather than the magnets.

[KRamone27]

I wonder what would cause a magnet to lose its power. Maybe being exposed to a stronger magnet, having the polarity of the magnet facing the wrong way?

[Mr. Bill]

Magnets can lose strength from outside influences such as magnetic fields, large transformers, etc., but these would be unusual cases. In most cases of pickups "wearing out", it's the owner's ears. In any case, they can be re-magnetised either by using a magnetiser or by using a really strong permanent magnet.

In Desert Surfer's case it sounds like the pickup had a broken wire or a bad connection.

Dub- When you say 3-4 ohms, do you mean 3-4 K (thousand) ohms? If they really are 3-4 ohms they would be the same as a dead short and wouldn't make any sound.

Fender pickups were/are wound directly onto the magnets. Sometimes with age the insulation on the magnet wire will breakdown. This could be from corrosion or physical abrasion, so sometimes they will make electrical contact with one or more of the magnets causing only part of the coil to short out, thus reducing the dc resistance and signal output. The worst case will be when the magnet wire actually breaks and the pickup dies completely.

[Dennisthe Menace]

Mr. Bill posted:

In any case, they can be re-magnetised either by using a magnetiser or by using a really strong permanent magnet.

What would be involved in this kind of procedure? Is this something that anyone can do?
I've got a little experiment going on with a cheap p'up, and I'm in one of those 'experimental moods'

[oipunkguy]

hey gang,

I remember hearing from seymour duncan that magnets can lose there strength to such things as simple as dropping the pickup on the ground hard enough, and strong changes in temperature. I suppose a pickup could also start to lose it's strength if the copper wire starts to corrode, but it wouldn't be long before the pickup just stopped working.

[Mr. Bill]

Dennis: Check the StewMac site, I think they still sell a super magnet set that they sell as a remagnetizer kit.

All you need to do is to get two strong magnets, mount them opposite each other in such a way as to create a field that you then run the pickup magnet through to charge or recharge it. Some people mount them to the faces of a vise so that they can adjust the field size to better fit the magnet that they are working on. It's been a while since I've checked the StewMac site, I'll try and get a link for you.

oipunkguy: Yes, physical force and heat can cause changes to a magnets strength, but I read somewhere, that it would take a lot of punishment to cause the magnet to lose enough charge for it to be noticable in a guitar pickup. The pickup would be destroyed because of the physical forces (broken wires or melted bobbins) before the magnet was greatly effected.

If you drop a typical Fender single coil pickup and it lands on one of the polepieces, the likely result will be that the magnet will be forced in or out of the flatwork causing the magnet wire that is pressed up against it to break.

There are thousands of vintage guitars with original pickups that have been treated badly through the years, but they still seem to sound ok.

[Dennisthe Menace]

Thanks Bill, Ima gonna check that out .

[Mr. Bill]

http://www.stewmac.com/shop/Tools/Clamps,_support_tools//Guitar_Repair_Magnets/Instructions/i-5967.html#details

Here's the link to the StewMac instructions. Scroll down towards the bottom of the page, after the rewinding section.